[asterisk-dev] New frame type for IAX: AST_FRAME_RAW ?

[Roger Schreiter]

Hi,

I would like to be able to bring a further ISDN feature to
IAX: "data call".

I just learned, that app_ppp and app_zap_ras are already
using the ISDN feature of "data call".
Further I learned from wiki, how to put PRI channels into
"data call" mode instead of "voice call" mode.

Anyway, one may whish to transport ISDN raw data to another
asterisk box or to a modified iaxmodem, also supporting
the new feature of ISDN raw data.
Imho, this won't be much effort using IAX. I would like to
make some tests and experiments about this.

First of all, I would like to know, whether my attempt
is the right way:

I would either introduce a new frame type for IAX, e.g.

#define AST_FRAME_RAW 11 /* digital raw data */

When asterisk does link an ISDN data call channel to an
IAX channel, it will send the ISDN data as IAX AST_FRAME_RAW
frames, and will accept from the IAX channel only those
AST_FRAME_RAW frames in order to send them to the ISDN channel.


Alternative:

Maybe it would be more smooth from the pbx view, better not
to introduce a new frame type, but a new "voice codec type"
which could be called AST_FORMAT_RAW.

In this case, one could use the existing negotiation method in
order to get the right data types connected. When on the ISDN
side the mode is "data call", it will only support the pseudo voice
codec "RAW".


Please tell me any hints, what you think about my ideas!
Any idea, how to make better, is welcome!


Roger.